All capuchin monkeys are clever¡­
But capuchins in captivity show dazzling feats of intelligence unheard of in the wild
Why should this be?
To solve this puzzle we put capuchins to the test.
The result may overturn everything you thought you knew about monkeys.
For their size, capuchins have the largest brain of any monkey¡­
and it never rests.
They are great conquerors¡­
the most widespread monkeys in all the Americas
The many varieties are all inquisitive and resourceful.
This is the most adaptable group of primates on the planet.
They forage where other monkeys fear to tread,
from the water's edge¡­
¡­to the open grassland.
Sharp eyes, nimble fingers and a lively mind¡­
even camouflaged prey has no chance.
Capuchins are so successful because they can find food anywhere
- but it's the way they find it that is the key.
Most types of monkey eat a lot of fruit.
But all differ in how they survive when this staple runs out.
Some turn to nuts or gum, others to leaves¡­
The Capuchins' solution?
That huge brain helps them to find things hidden from view¡­
and hidden from other kinds of monkey.
This is the secret of their success.
Capuchins can imagine what might be hiding behind a palm frond
¡­ or lurking down a hole.
For them, out of sight, is never out of mind¡­
A large brain can memorise all the best hunting locations...
¡­and the ability to recall a previous experience
could make the difference between getting stung¡­
and getting honey.
Some days there's barely a moment to rest.
The mental alarm clock is ringing¡­
it's time to be somewhere else¡­
Being brainy allows you to schedule your day¡­
¡­the monkeys are arriving in the mangrove,
just as the tide is falling.
The dropping water exposes shellfish.
Collecting clams would seem the easy part.
They are certainly full of meat,
but it's all locked up behind closed doors.
Perhaps grasping hands guided by a big brain can solve the problem.
The trick is to bang the clam hard and often.
Eventually the muscle inside will relax,
and the shell can be opened.
At least 20 capuchins are now putting this theory to the test.
Ten minutes on and the clams are still holding it together.
This is hardly 'fast food'!
The young watch avidly and most will learn.
Although it takes perseverance and foresight to open clams,
hitting shellfish against a branch needs good technique rather than great intelligence.
Even so, some monkeys never really get to grips with clam cracking!
For those that persevere with a good technique,
the clams are starting to yield,
and rewards are being claimed¡­
¡­although a few fall short of expectation.
Opening clams is good problem solving,
but it hints at a greater potential.
Capuchins in South Carolina are helping scientists
explore the limits of monkey intelligence.
This honey has no stinging bees...
but researcher, Ted Evans, will add some obstacles of his own.
First, a tough plastic sheet is used to seal the top of the tube.
This is lowered into a stronger tube that is taller and harder to reach into.
Four tools are available:
a rock, a wooden block,
a leafy twig and some building bricks
- but it's rather unclear how any of these will help.
Vulcan takes up the challenge...
He's done this test before,
but no one taught him how to do it.
It's hard to see how banging two rocks together will help,
but Vulcan's determination suggests he has a plan.
A flint knife!
Vulcan has transformed the rock into a cutting tool!
The first piece isn't sharp enough to cut the plastic ¡­
so he tries another with a keener edge.
This is not easy!
At last! The seal is broken
- but the honey is still out of reach.
Vulcan switches to the branch and begins stage two.
He's stripping away way the leaves and the bark¡­
to make a probe.
Finally, he can reach the honey.
This goes way beyond 'banging a clam'.
This is true tool use -
the holy grail of intelligence research.
What's more, combining different tools in sequence
is tool-use of a most sophisticated kind.
Sceptics might claim that Vulcan has been trained to do this
and has no real understanding of the task.
To test this, the experiment is repeated,
but coloured chips are used to represent the tools.
The black chip buys a rock,
the yellow a twig, and so on.
Black - that's the rock.
With the tool he requested, Vulcan goes to work on the plastic seal.
Now he'll need the twig, which is yellow.
A brick is not what Vulcan asked for!
That's better!
Not only is Vulcan entirely self-taught
but, no matter what the task,
he knows exactly which tools are required
and precisely the order in which to use them.
Most of Ted's monkeys use tools,
but some catch on quicker than others.
Of course, many tools don't exist in the wild,
but capuchins are great improvisers.
Costa Rica in the dry season
and monkeys are searching for drinking water in tree-holes
¡­ but these can be very deep and the water hard to reach.
The smartest monkeys know that tails make the best sponges.
As the forest dries it becomes harder to find food in the treetops.
The best hunting grounds now border the rapidly drying rivers.
The water itself is too stagnant to drink but the bank side is lush,
and for a monkey as curious and canny as a capuchin,
there are all kinds of dining opportunities.
This monkey's ability to eek out a meal from the most unlikely nook or cranny
can be a life saver ¡­
¡­ on the other hand,
their inquisitive nature constantly gets them into trouble.
Snakebite is a common cause of death among capuchins.
The hysteria is contagious, but it won't last.
This snake is perfectly harmless.
Most youngsters learn to identify predators correctly before they're adults,
and those that don't, start to be ignored by the rest of the troop!
Capuchins are smart enough to work out which of their fellows give reliable alarm calls,
and which can't be trusted!
Throughout their extensive range capuchins need to be ever alert.
There's no mistaking this predator.
Jaguars are always on the lookout for bite-sized monkeys
that have strayed on to the forest floor.
This call means 'cat'.
Monkeys heed this alarm without hesitation.
No monkey is a match for a jaguar.
But the rapid retreat is not what it first appears¡­
It seems that the capuchins climbed the cliff to arm themselves.
Even when the cat appears to have fled,
the monkeys take no chances.
There's no doubt that brains really can beat brawn.
It's extraordinary what a small monkey can achieve
through creative use of its surroundings,
and not just against predators.
These forests have a wealth of resources
and capuchins have found some very novel ways of using them.
When in season, oranges are seized with great enthusiasm.
The monkeys peel their skin but, curiously, don't eat them.
Instead, they spread citrus juice through their fur,
which sets off a frenzy of rubbing and drooling.
A large orange is hard to share
so disagreements are rather common.
This is clearly good fun,
but could there be another reason for it?
A different plant may shed light on the behaviour.
Piper leaves are rarer than oranges and even more sought after.
But the reason for their use is better understood.
This plant is considered medicinal by the local people,
who apply it to their skin to repel insects and disinfect wounds.
We can only assume that capuchins do the same,
and this is also why they use oranges.
Whatever the reason, the plant is passed around
and everyone joins the party.
Such good-natured sharing is extremely rare in monkeys
so could an affinity for co-operation be another reason for the capuchin's success?
This theory is being put to the test back in Carolina ¡­
A pot of hazelnuts... and the flint that's needed to open the lid.
You need both to get a nut,
but they are separated by a see-thru barrier.
Vulcan has the rock,
but can't reach the nuts.
Virgil has the nuts but knows he can't eat them without a rock.
Vulcan quickly offers the tool.
He must hope Virgil is smart enough to open the lid
and fair enough to cut him in on the spoils.
Virgil is struggling;
he doesn't have his friend's skill.
And Vulcan is getting impatient.
The flint is finally through the lid,
but can Virgil be trusted to share the nuts?
With Vulcan out of reach, it must be tempting to take the lot!
Three nuts ¡­ a fair share!
Vulcan and Virgil have used teamwork to beat the system,
but can capuchins really have a sense of fair play?
Ted gives Vulcan a white chip, which can be exchanged for food
- in this case, a dried biscuit.
An identical token for Virgil
but in return he gets a juicy grape - a far better exchange.
Virgil's back for seconds,
but this time Vulcan sees him get the grape.
He now expects one too.
Biscuit? That's not fair!
Virgil's back again¡­
¡­another grape!
Vulcan is losing his composure ¡­
This injustice is too much!
He was happy with biscuit, but that was before Virgil got grapes.
Now he'd sooner have nothing than be short-changed.
It's a point of principal.
Virgil returns, so Vulcan suspects Ted of readying another grape.
It must be in there somewhere.
At last - a succulent grape.
Vulcan and his friends show us that capuchins understand justice,
display extraordinary feats of co-operation,
and are perhaps the best tool users in the Animal Kingdom.
So why do capuchins in the wild never seem to show these levels of intelligence?
Perhaps we haven't been looking in the right place ¡­
This is the Green Wing Valley in Brazil,
and what has just been found here is rocking the scientific world.
The discovery was made among the magnificent cathedral-like rocks
that rise out of the jungle.
Giant stone anvils litter the forest.
They look like they could only have been made by humans
¡­ but they have not.
Capuchin monkeys bring nuts from miles around to these anvils for cracking.
We've seen these monkeys using tools in captivity,
but this is the first time it's ever been seen in the wild.
We knew these monkeys had the potential¡­
this could start to make sense of the 'capuchin enigma'.
To watch wild monkeys wielding a hammer is a remarkable sight,
but the full story is truly incredible.
Elsewhere in the valley another troop is on the search¡­
This is the harvesting site several kilometres from the anvil.
Fresh palm nuts¡­
tapping will reveal the ripest ones.
These are slightly easier to pluck ¡­
but they still aren't ready to eat.
The first stage is to peel away the fibrous husk.
This exposes the nut to the elements and accelerates the ripening process.
Next, the nuts are dropped to the ground where they mature in the sun.
They take many days to fully ripen
¡­ however the ground is littered with other nuts
that the monkeys prepared on previous visits,
and these are now tested for readiness.
Those that sound right are collected
and transported several kilometres through the forest to the anvil.
As long as they prepare a few nuts every time they come to harvest the ripe ones,
return trips will always provide nuts ready for cracking.
A triumph of planning and foresight.
But the best is yet to come.
The hammers are polished and look nothing like other rocks from the area.
Despite weighing more than a capuchin,
they have somehow carried them here from the river,
several kilometres in the other direction.
There is more to using these tools than first meets the eye.
Not only must you choose the right hammer
- for each is best with a certain kind of nut
but you must correctly position your nut in one of the slots on the anvil.
Different 'sockets' suit different nuts.
The correct choice makes the difference between success and failure¡­
Begging for nuts is rarely successful,
but at least being beside the anvil is the best way to learn.
As usual, every monkey has its own style of doing things...
but nut on nut is never going to work.
Even the slower monkeys eventually learn
and the technique is passed down from generation to generation.
From the wear on the anvils
it's clear this has been happening here for hundreds of years.
It seems like a lot of effort for very little nut.
But few other foods are available.
It's only the ability to crack nuts
that allows these monkeys to live here.
This is a vital clue.
Captive monkeys seem so intelligent
because we challenge them with problems and tasks.
A natural environment that does the same,
forces them to use mental reserves that all capuchins must have.
This discovery is the missing part of 'the monkey puzzle'
we thought we may never find.
We have underestimated our monkey cousins
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